Or maybe you should find the difference between sort and sort! (note that mutating the input is a bad thing)

The following sorting snippet works in my IRB but doesn't work in the tests that are run.

Maybe because your console automatically prints out the returned values?

I don't know what you confirmed, but it works in both MRI here.

Issue clearly specified.

"The following sorting snippet works in my IRB but doesn't work in the tests that are run."

This is confirmed by adding a "p s.sort" in the code.

Issue not specified.

This is a sample test. If you can't pass it, your code is 100% wrong.

This seems broken on Ruby (both MRI versions). The following sorting snippet works in my IRB but doesn't work in the tests that are run.

irb(main):001:0> a = ["turns", "out", "random", "test", "cases", "are", "easier", "than", "writing", "out", "basic", "ones"]
=> ["turns", "out", "random", "test", "cases", "are", "easier", "than", "writing", "out", "basic", "ones"]
irb(main):002:0> a.sort
=> ["are", "basic", "cases", "easier", "ones", "out", "out", "random", "test", "than", "turns", "writing"]